Piston brake valve



July 16 1946- R. B. CAMPBELL 2,404,122 v PIsToN BRAKE vVALVE Filed Maron s, 194s 2` sheets-sheet 1.

l man THE /HM July 16; 1946. R. B. CAMPBELL 2,404,122

PIsToN BRAKE VALVE l Filed Ma'IGh 30, 1945 2 Sheets-Sheet 2 f4 44 s 57 Jeff 6e 37 J0. ff 13 43 66 36 a1 as J2 29 47 ax t 67 0 .6a /W .63 a l l ArrozA/Eys.

Patented July 16, l1946 PIs'roN BRAKE VALVE Rodney B. Campbell, Van Nuys, Calif. l Application March 30,1943, serial No. 481,078

(C1. l30s- 54) 9 Claims.

This invention primarily relates to a fluid braking system, and more particularly to such a system having particular utility in the aircraft industry, and therefore will be described in connection therewith. Certain parts and combinations of my system, however, are readily susceptible to other uses, and I do not intend to be limited to the preferred embodiment described. Y

Aircraft, and particularly aircraft of the large, heavy transport type, are commonly equipped with fluid operated brake systems, in which an operating fluid, such as oil, is transmitted from a source of supply such as a pump through suitable conduits and a valve device to the liuid operated brakes of the vehicle. Valve means are normally provided in the line of the conduits for opening the conduits and permitting the operating fluid to flow to the brake mechanism to operate the same, and the normal-operating pressure of the operating fluid is commonly held below two hundred pounds per square inch. In normal operation of such prior art systems it has been discovered, however, that when the brakes are applied to stop the travel of a heavy vehicle, such as an airplane, a large amount of friction is developed in the operation, which dissipates in the form of heat into the brake mechanism. Consequently, the column of operating fluid used to actuate the braking mechanism also absorbs a considerable amount of this frictional heat, which immediately expands the fluid, causing a large increase in the pressure thereof. This pressure increase may quickly raise the pressure of the operating fluid from the normal Working pressure of, for example, 200 pounds per square inch, to an abnormally high pressure, sometimes attaining2000 pounds per square inch or more.

This abnormal rise in pressure of the operating fluid has a number of disadvantages. For example, it creates an abnormal and dangerous pres,- sure strain on the hydraulic equipment. Furthermore, and what is more serious, the increase in pressure increases the braking action, tending to lock the brakes of the airplane, which may oper-4 ate unevenly between the several brakes, causing serious accidents with their attendant loss of property and life.

It is therefore a primary object of my invention to provide an improved brake valve for aircraft and other vehicles in which the pressure of the operating fluid delivered to the braking mechanism of the vehicle is at all times automatically maintained at an adjusted predetermined maximum.

It is a further object of my invention to provide a novel valve device which will accomplish the foregoing object, and which includes a main valve and an auxiliary valve, the latter being automatically operable in response to a rise in pressure of the operating fluid to relieve the pressure thereon and maintain it at an adjusted predetermined maximum.

Another object of my invention is to provide a fluid operated braking system including a-valve device, in which the operation of the actuating or control mechanism, normally manually oper,- ated, is not critical to maintain'a predetermined braking pressure applied by the operating fluid.

Another objectof my invention is topro'vide a valve device'as described above in which the main valve is fully balanced hydraulically and in which the exhaust valve is designed to open automatically upon any slight abnormal Vrise in the pressure of the fluid delivered to the brakes. While valves of the general type of my valve are in wide use in the aircraft industry, by my specific construction and arrangement-of parts I have provided a valve which is more positive in operation and more delicate in its response characteristics than the prior art valves of which I have knowledge, and my 'specific construction is consequently of major importance. Y Y

Other objects and advantages will become evi,-V dent in the following specification and inthe drawings, in which: Y

Fig. 1 is a longitudinal vertical sectional view taken through ,my valve, showing the valve in idle position. e'

Fig. 2 is an end View of the right-hand end o the valve as shown in Fig. 1.V

Fig. 3 is a view similar to Fig.v l, but showing the parts in a first operating position in which high pressure fluid is being supplied through the valve.

Fig. 4 is a view similar to Fig. 3, but shows, the parts in a second operating position in which high pressure'has built up within the valve to open the auxiliary exhaust valve to permit the pressure to drop.

Fig. 5 is a cross-sectional view taken on the line 5-5 of Fig. l. Y

Fig. 6 is a cross-sectional view'taken on the line 6--6 of Fg- 1 Referring to the drawings, I show a housing Ill having a main bore II, a portion I2 of which is of slightly reduced diameter to provide an annular shoulder I3 therebetween. The housing `Ill is provided with a suitably threaded inlet port I4 which is adapted to receive the end of a pipe yor tubing I5 leading from a suitable source of high pressure fluid (not shown) The large end of the main bore I I is counterbored at Il and preferably provided with straight threads I8v which receive a pipe fitting I9 having a suitably threaded supkply port 20' thereinadapted to receiveY the end ing ring 22 adapted to form a fluid-tight seal be- Y tween the pipe litting and the mainbore Il. y A 'I'he pipe fitting I9 engages and holds in place against the annular shoulder 1 I3 a-tubular valve sleeve member 211 whichis provided with an an-` Y nularfrecess 25 which registers with the inlet port` I4. The valve sleeve member' 24 is also provided!v with suitable annular packing rings 26 capable Qi forming duid-tight seals between the valve sleeve member and the bore Il on each side of the an` nular recess 25. The valve sleeve member 24 is pression sprin'g 55 disposed in the annular space .413 and also engaging against sleeve member 24.

Secured to an end 51 of the housing I is a split collar member 58 secured to the end 51 by a suitthe end of the valve able belt BI, as best shown in Fig. 2. VThe split provided with a minor bore 21 and a major bore"-Vr 28 oi' somewhat larger diameter, the valve sleeve,Iv y

member being of reduced external diameter con-v centric with the major bore l28 to provide a reduced 'annular portion 2Q. A Communicating be tweenrthe annular recess 25 `and the minor bore` 21are ,aj plurality of Ycrircurnferentially spaced radialjmainvalve'ports 3l, land communicating through the V'reduced annular portion 29 of the .valve ,sleeve area pluralityof Vcirc umferentially spaced auxiliary ports 32. Y'

i Disposedrin theY minor :bore 21 of thesleev'el member 24 is a tubular main valve member 33 adapted for axial movement in the minor bore andl ground `for a close sliding iit therein Vand provided with an annular doughnut packing ring 3S. .Thev main valve member 33 is provided at` I its outer end Vwith an annular head 34 of slightly K greater diameter than the 'mino-r bore 21, theV head-'being provided with an inwardly bevelled seating vface 35 which terminates on its inward end in Yan annular groove 36 formed on the periphery of the mainv valve member.

Iii is a relatively weak compression spring 3l adapted normally to urge the main valve member As willbe noted, when the main, valve member 33 is in seated position against the valve sleeve member 24, Vas shown in Fig. l, the inner lendr39 of the main valve member extends a substantial distance into the Vmajor bore 28. Y f

Disposed in the ma-j'orb-ore '28 of the. ,valve` sleeveY member 2d for axial movement therein is l Engaging between the kannular head 35 and the pipe fitting collar 5S is provided with ears B3 and 64 between which .an actuating lever 65 is positioned, the acf' tuating Vlever being pivoted on a pivot bolt 62. The upper end of the actuating lever 65 is suitably 'connected to a brake pedalfor other actuating mechanism adapted to rotate the actuating lever iiabout the pivot VF2. The lower end ofA the a'ctuating ylevert?, is provided with a yoke 66 in which an anti-friction roller 6,1 is rotatably mounted on Aa cross pin 68. As illustrated in Fig. 1; the anti-friction roller 61 vis adapted to engage the end wall --o'f the cylindrical actuating mem- As -be understood, ininstalling my device in a hydraulic system, the high pressure tubing I5 is .preferably connected to a high pressure pump orother source of high pressureluid (not shown) adapted to supply operating uid under a relatively high pressure such as, for example, 1000- Y. pounds per 'square inch, vto the valve device. The

a cup-shaped auxiliary valve member 4B of some- 'Y what greater external diameter than that ofthe main y valve member 33. The auxiliary valve i member 4B has a central cavity 4I and is provided Yat'ts open end with a conical seating face i2 gagement with the main valve member 33, fluid communication' is provided between the supply port 2i), through the interior of the main valve member 33, and through the auxiliary valve ports 32 with an annular space 443 `formed between the reduced annular portion 29er the valve sleeve member 24 and the portion I2 of the main bore As will be noted from Fig. l,

supply tubing 2| is preferably connected to a hydraulic brake or brakes (not shown) adapted to be actuated by the operating uiddeliveredby the inlet tubing I5 but at aY substantially lower fluid pressure, and the exhaust pipe 45 is preferably connected to a llow pressure discharge or the fluid reservoir adapted to supply iiuid to the high pressure sourceV (not shown). Although my valve device is particularly designed -for supplyingV operating fluid t0 a hydraulic brake system, it will be apparent that the valve device may be used in otherfconnections without departing from' the 'spirit Vof my invention.

' In operation, when my valve device is 'not being actuated to 'supply high pressure operating uid to the hydraulic brake system, the parts 4are lnormally'in the idle position illustrated by Fig. 1. In Lthis position, the actuating lever is in its released position, permitting the cylindrical a-ctuating member 5I to be moved into its rightward position by the compression spring 5E, so that the annular ange 155 seats against the housing I 0. In this position, the actuating spring 49 is fully expanded, thus 'permitting the auxiliary valve member-ll!! to Iremain in its open-position as shown in 1'in which fluid communication is provided between the supply por-t 2i? and theexhaust port @E through-'the 'bore of the main valve member 33, the auxiliary valve port-32, and the annularv space d'3. Thus, in this idle position the hy- I I, which in turn communicates with an exhaust y suitable point of low'pressure discharge Vor Vexv haust (not shown) The closed end of the auxiliary valve member 4B is provided with a central boss 41 which regise ters with a spring follower element 43 which in turn is engaged byY an actuating spring '49. The other end of the actuating spring 49 engages the end wall 50 of a cylindrical actuating member '5 I journalled in a cylindrical opening 52 formed in V"pression spring 56. Such `leftwa'rd movement also o f'lthe cylindricalactuatingrmember 5I to move the actuating mem-ber to the -left toward the position illustrated in Fig. 3. Leftward movement of the actuating member 5I compresses the combodily moves'the actuating spring 49 to the left, moving with it the cup-shaped auxiliary valve member 49, until the conical seating face 42 thereof seats on the inner end 390i the main valve member 33. Continued leftward movement of the auxiliary valve member 40 then moves the main valve member 33 to the left toward the position shown in Fig, 3, in which communication is vprovided between the inlet port I4 and the supply port 29, through the annular recess 25, the main valve ports 31,' and the annular groove 36. It is to be noted that when the main valve member 33 is in its closed position as shown in Fig. 1, high pressure fluid from the inlet tubing I5 fills the annularv groove 36, but since the ends of the annular groove are equal in cross-sectional area, the main valve member is hydraulically balanced as to such high pressure fluid. Consequently, it requires little force exerted through the auxiliary valve member 40'to move the main valve member 33 from the closed position shown in Fig. 1 toward the open position shown in Fig. 3. It is to be noted, however, that the compression spring 3l resists leftward movement of the main valve member 33, and that as the spring Slis compressed by such leftward movement its resistance to the movement increases. Consequently, the actuating spring 49 lis also/increasingiy compressed as the actuating lever 65 is rotated from its released position shown in Fig. 1 to its open position shownin Figs. 3 and 4, in which it applies a predetermined maximum fluid pressure to the brakes, such as, for example,'200 pounds per square inch. Thus, the main valve member 33 may be moved by the actuating lever 85 to any degree of opening between its closed position shown in Fig. 1 and its open position shown in Fig. 3. If'the main valve member 33 is moved to its open position shown in Fig. 3, obviously the full fluid `pressure for which the actuating spring 49 isV designed (for example, 200 pounds per square inch) will be applied -to the hydraulic brakes through the 'supply tubing 2l. The main valve member 33 acts as a pressure reducing device to reduce the fluid pressure applied rdegree to which the main valve 33 is opened, and

that the operator may apply any desired fluid pressure on the brakes up to the maximum pressure for which the spring 49 is designed by simply controlling the amount of rotation of the actuating lever 65.

So long as itis desired to apply a predetermined fluid pressure to the hydraulic brakes, the actuating lever 65 is retained in its operating position, such las shown in Fig. 3, .thus maintaining the main valve member 33 in its open position as shown therein. The device is designed so that the main valve member remains in its set open position so long as the fluid pressure in the suprise in pressure is communicated through the.,

bore of the main valve member 33. to the interior of the auxiliary valve member 40, tending to move the latter to the right against the compression ofthe actuating spring 49.` The actuating spring 49.is ldesigned so that, when compressed in the position illustrated in Fig. 3, it maintains the auxiliary valve member 40 in;pressure engagement and forcesthe auxiliary valve member 40 to the right to the position illustrated in Fig. 4, thus further compressing the actuating spring.

Upon rightward movement of the auxiliary valve member 40, the main valve member 33 also moves to the right in response to the action of the compression spring 31 bearing thereon, so that the inwardly bevelled seating face 35 of the main valve member seats on Ithe end of the valve sleeve member 24 i-n its closed position, as illustrated kin Fig. 4, before the auxiliary valve member 40 moves out of engagement with the main valve Vmember 33. Thus, upon such a pressure rise in the supply port 20, the main valve member 33 first closes communication between the inlet port I4. and the supply port 20, and then continues the movement of the auxiliaryvalve member 4u to the right to the position shown in Fig. 4 to open communication between the supply port 20.and the exhaust port 44. Operating fluid is then allowed to bleed from the supply tubing ldirectly into the exhaust pipe 45 to reduce the iiuid pressure in the supply tubing. This pressure drop continues until the uid pressure in the supply tubing 2 i and supply port 20 drops lto thev value for which the actuating springY 49 is compressed by the setting of the actuatingA lever y65, such as, for example, 200 pounds per square Y in the supply port 29 drops below the pressurefor which the actuating sprl-ng 49 is set by the actuating Vlever 65, and thus there is no fluttering or' chattering of the main valve member on its seat. It will thus be understood -that with the actuating lever 65 moved to the position shown in Figs. 3 and 4, a predetermined fluid pressure will be supplied to and held in the supply tubing 2l, and that any rise in fluid pressure inthe supply tubing 2| will cause the main valve member 33 to move to closed position, as illustrated in Fig. 4, and the auxiliary valve member 40 to move to open position to permit a reduction in pressure. A'I'his action is entirely automatic, and due to the simplicity of the parts and construction is adapted for and capable of holding the fluid pressure in the supply tubing 2l within very narrow limits of, for example, 5 to 10 pounds per square inch. Furthermore, the specific design of the parts and construction prevents chattering of the valve members, which has been a source of much difficulty in such valve devices heretofore. It will also be evident that if the actuating lever 65 is rotated in a clockwise direction beyond the position shown in Figs. 3 and 4, .the main valve member 33 will be additionally moved to the left to furtheropen communication between the aning toincrease the'Afluid"pressurev supply tothe supply tubing 2l. VAs soon as such pressure rise overbalances the compressive force exerted lbyv `the lactuating spring 49, however, theY 4auxiliary valve member 4i] will openas described above to bleed off'this excess pressure. v"Il'rus it is 'impos- `sible for the operator `to apply a substantially higher fluid 'pressure to the hydraulic brakes than that vfor which the Vactuating spring i9 is de-l signed; which is an important safety `factor lin the device. 1 l

VAs will be understood, upon the .return of Athe actuating 'lever to released position, 4as shown in Fig. l, the main valve member '33 under faction of the compression spring 31 willirclose as illus-` trated therein, andthe auxiliary valve member 40 will move to its open po's'itionas alsoVV illustra-ted therein.

' It will also be understood 'from the foregoing; desoription that any-desired'iluidl pressure mayl be supplied to the supply tubing 2l, vup to the. predetermined maximum pressurev for which the actuating spring t9 isdesigned. Thus, if the l actuating spring 9 is designed to permit a max- `im-urn pressure application of 200 pounds Yper square inch, by only partial rotation of the actuating lever't the operator may'apply any desired lower fluid'pressure to the brakes, such as, for-example, v50 pounds per square inch. Se long as the Aactua-ting lever 65 is maintained in such in- Vthe supplied pressure tends Vto drop, the actuat-V Ving, spring 49 vwill slightly open the main valve 3, memberrSS to permit the pressure to again build i YuptOi the desired application. l will operate in substantially the same manner're- IThus, the device gardless ofthe degree to which the main valve member is opened bythe operator.

My valve device is very sensitive to changes in fluid pressure in the supply tubing ,2| and -operates to hold a desired predetermined fluid pres'- 21.

sure in the supply tubing within very close limits, which has not been possible with the prior art devices of which I have knowledge. This `supethat the 'main valve member 33 ,is substantially l hydraulically balanced when closed, its end 439 being of substantially the same area as its .other end, and in combination therewith the area of end 39 of the main-valve member 33, a self-cen- 1 tering seating thereof being attained bythe conii cal seating face 42 whichv compensates for any possible slight axial misalignment of the valve members.

Although I have shown and described a preferred embodiment of my invention which has l particular application -to hydraulic brake sysf tems for aircraft, it will be appreciated that .I

do not intend to be limited to such a construction, butpdesire to be'aiforded the full'scope of the following claims.

I claimV as my invention: y l. In a valve device,r the combination of a l housingv having aninlet port, a supply port, an exhaustpcrt, and a valve bore; a tubular' main 'valve member in said 4bore having an annular 1 'headon one end thereof of `only* slightly larger 'diameter than said bore and having a rvpassage therein,`"said main valve member being axially movable Vin said bore from a closed position in which communication between said inlet port and' said Ysupply port 'through said passage is closed by said head seating against a shoulder formed at one end ci said bore to an open position inwhich said passage provides fluid communication between said inlet port and said supply port; means foryieldably maintaining said main valve member in said closed position; a cupshaped auxiliary valve member axially movable relative to said main valveV member and having Van inwardly bevelled seating face on an open end `thereof adapted to seat `onY the periphery o' one end of said main valve member; a movable actuating member axially movable in said housing;

' spring means operatively connecting said actuating member and said auxiliary valve member so that said auxiliary valve member may remain out o'f engagement with said main valve member to provide fluid communication between said suppl-y port and said exhaust port through said main valve member; means for moving said actuating member axially froma.` first position to oper-ate through said spring means rs'tto `cause said auxiliary valve lmember to engage said main valve 'member so that said seating seats on said periphery to close said fluid communication be-V tween said supplyportY and said exhaust port, and upon 'continued axial movement of said actu-v ating member then to rnove said `main valve member from said closed positionl to saidv 'open position; and means lor normally urging said actuating member to said first position.

2. -In a valve device, the vcombination of a housing having a bore therein and having an inlet port, a supply port, Yand an exhaust port; a tubular valve sleeve stationarily disposed in saidv bore and having a lminor bore and a major bore axially aligned therein, said valve sleeve having a main valve port communicating between said minor bore and said inlet port, and having an auxiliary valve port communicating between said 'major bore and said exhaust port; a tubular main valve mem-ber in said minor bore having a pas- Vvsage therein, said main valve member being axi- Yrior functioning is due in large part to the facty theauxiliary valve member 40 exposed to the fluid pressure of the supply port 2i) is as large .as n possible# This latter feature is achieved by tel-escoping the auxiliary valve member 4l! over the ally movable in said minor bore from a closed position in which communicationx between said main valve port and Said supply port through Ysaidpassage is closed to an ope-n position-in which said passage provides fluid communication between said main valve port and saidpsup-plyY port; abuis-shaped auxiliary valve member in said maior bore and axially movable relative to Vsaid main valve member, said auxiliary valve member normally being out of engagement with said main valve member so that huid communication is provided between said auxiliary valve port and said supply port through said main valve member; an actuating member in said housing; spring means operatively connecting said actuating member and said auxiliary valve member;

and means for moving said actuating member -to cause said spring means iirst to move said aux-V iliary valve member, into engagement with said main valve member to close Huid communication between said auxiliary valve port and said supply port, and then to move said auxiliary valve member and said main valve member to move said `main valve member from `said closed position to said open position, f

n In a valve device, the combination of:V a housing having a vbore therein and having an inlet port, a supply port, and van exhaust port; a

9 tubular valve sleeve stationarily4 disposed in said bore and having a minor bore anda major bore axially aligned therein, said valve sleeve' having a main valve port communicating between said minor bore and said inlet port, and having an auxiliary valve port communicating between said major bore and said exhaust port; a tubular main valve member in said minor bore having a passage therein and having an annular head on one end thereof of only slightly larger diameter than said minor bore, said main valve member being axially movable in said minor bore from a closed position in which communication between said main valve port and said supply port through said passage is closed by said head seating against one end of said valve sleeve to an open position in which said passage provides fluid communication between said main valve port and said supply port; a cup-shaped auxiliary valve member in said major bore and axially movable rela' tive to said main valve member, said auxiliary valve member normally being out of engagement with said main valve member so that fluid communication is provided between said auxiliary valve port and said supply port through said main Valve member; an actuating member in said housing; spring means operatively connecting said actuating member and said auxiliary valve member; and means for moving said actuating member to cause said spring means iirst to`move said auxiliary valve member into engagement with said main valve member to close fluid communication` main valve member from said closed position to said open position.

4. In a valve device, the 'combinationoff 'a` housing having a bore therein and having an inlet port, a supply port, and an exhaust port; a

tubular valve sleeve stationarily disposed in said bore and having a minor bore and a major bore axially aligned therein, said valve sleeve having a main valve port communicating between said minor bore and said inlet port, and having an auxiliary valve port communicating between said major bore and said exhaust port; a tubular main valve member in said minor bore having a passage therein, said main valve member being axially movable in said minor bore from a closed position in which communication between said main valve port and said supply port through said passage is closed to an open position in which said passage provides fluid communication between said main valve port and said supply port;

a cup-shaped auxiliary valve member in said ma;`

jor bore and axially movable relative to said main valve member, said auxiliary valve member having an inwardly bevelled annular seating face on an open end thereof adapted to seat on the periphery of one end of said main valve member,

said auxiliary valve member normally being out of engagement with said main valve member so that fluid communication is provided betweenA said auxiliary valve port and said supply port through said main valve member; an actuating member in said housing; spring means operatively connecting said actuating member and said auxiliary valve member; and means for moving said actuating member to cause said spring means first to move said auxiliary valve member intol engagementwith said main valve member to close fluid communication between said auxiliary valve port and said supply port, and then to move said member to move said main valve member from said closed position to said open position.

5. In a valve device, the combination of a housing having a bore therein and having an inletport, a supply port, and an exhaust` port; a tubular valve sleeve in said bore engaging a shoulder formed in said bore and having a minor bore and a major bore axially aligned thereirnsaid valve sleeve having a main valve port communieating between said minor bore and said inlet port,` and havingan auxiliaryvalve port commu' nicating betweensaid major bore andsaid ex-4 haust port; sealing means-adapted to formla duid-tight joint between said` valve sleeve and' said bore; a fitting threaded into one'endof said. housing and engaging said valve sleeve to hold the same rigidly in 'said housing; a tubular main valve member in-said minor bore having a pas-1 sage therein, said main valvemember` being axiallyfl movable in said niinorbore from a closedv positionin which communication ,between-said main` valve port and said supply port through said passage is closed'to an openV positionginwhich said'passage provides fluid 'communication between said main valve port kand said supply portfa cup-shaped auxiliary valve member' in'said major bore Vand axially movable yrelative to said main valve member, said auxiliary valve memberand said auxiliary valvefmember; and means for moving said 'actuating member 'to-cause saidf spring means first to move said auxiliary valve' member into engagement with said-mainuvalve member to close fluid communication between said auxiliary valve portand said supply port,l and then to Hmove said auxiliary valve memberand said main `valve member to move said main valve member from said closed position to said open position.

.6. In a valve device, the combination of:Y a housing having a bore therein and havingan inlet port, a supply port, and an exhaust port; a tubular valve sleeve rigidly secured in said bore and having a minor bore and a major bore axiallyaligned therein, said valvesleeve having a main valve port communicating between said mi nor bore and an annular groove in the periphery of said valve sleeve registering with said inlet port, and having an auxiliary' valve port com municating between said major bore and said exhaust port; a tubular main valve member insaid minor bore having an annular groove passage formed on its periphery adapted to register with said main valve port, said main valve member ybeingl axiallyV movable in said minor bore-` from a closed position in which communication between said main valve port and said ysupply port through said passage is closed to an open position in which said passage provides fluid communication between said main valve port and said supply port; a cup-shaped auxiliary valve member in said major bore and axially movable relative to said main valve member, said auxil-V iary valve'member normally being out of engage'- mentwith said main valve member so that fluid communication is provided between said auxiliaryi valve .port and said supply port through said mainvalve member; an actuating member in'saidj housing; spring means operatively connecting auxiliary valve member and said main valve said (actuating member and said auxiliary valve .memberj and means vfor moving said actuating member to cause said spring means rst 'to move Isaid` auxiliary valve member into engagement with said mainr valve member to close fluid communicati'on rbetween said auxiliary valve port and lsaid supply port, and then tomove saidV auxiliary valve member and said main valve member to move said main valve member from said closed l position to said open position. f 7."In` a valveY device, the combination of: a housing' having a main bore therein and having `an inlet "port, asupply'port, `and an exhaust port; la tubular valve 'sleeve in said main bore and havinga minor bore and a major bore axially aligned y Ylrtherein, said valve sleeve having an annular closed' position in which communication between `said main'valve port and said supply port'through .saidl passage is 'closed to an open position in which 'said'passage provides fluid communication e `between said main valve port and said supply `portffa cup-shaped' 'auxiliary valve member inr I said major bore andaxially A'movable relative to said main' valve member fr om anopen position inwhich it is out of engagement with said main `vtweeii said auxiliary valve port and said supply `port throughsaid main Yvalve member to a closed jp'osition, iniwhich git tengages saidv main valve I i Ymember to close such communicationjl an actuating member insaid'housing and movable in the same direction as said auxiliary valvemem- .ber; a compression spring disposed in said an- .nular space and engaging between said valve *sleeveand/said actuating member to tend to urge `saidactuating member away`v from said'auxiliary valve member to an inoperative position; an

actuating spring disposed between said 'actuatiing member and said auxiliary member and de- ;signed'so that? when saidactuating member is Y Vvvalve'rneinberv to open fluid communication be'- Y Y vide fluid communication between said. inlet port .and said supply port; a cup-shaped auxiliary [said inoperative position 'said actuating spring exerts substantially no force on said auxiliaryV valve member;A and means for moving 'said acltuating member against the action of said. com-y .lpression spring to apply force to said auxiliary valve member through said actuating spring lirst tomove said auxiliary valve memberint'o said lclosed lposition and then to move said'auxiliary valve member and said main valvey member to move the latter to its said 'open position. Y

8. In a valve device, the combination of: a

housing having an inlet port', a supply port, 1an

Iexhaustport,and a valve bore; ya tubular main valve member in said valve bore and having a V:passage therein, said main valve member being Eaxially movable in said bore from a closed position'in which communication' between saijd inlet `'port and said Ysupply port through said passage is member without changing substantially the area of said one end exposedv to the fluid pressure of Vsaid supply port; a movable actuating -member axially movable iny said housing; spring means operatively connecting said actuating member and said auxiliary valve member so that said auxiliary valve member may remain out of engagement with said main valve member to provide fluid communication between said supply port and said exhaust port throughv said main valve member; means for moving said actuating member axially from a iirst position toY operate through said spring means first to cause said auxiliary Valve member to engage said one end of said main valve member to close said iluid communication between said supplyport and said exhaust port, and upon continued axial movement of said actuating member then to move said main. valve member from said closed position to said open position; and means disposed between said housing and said actuating member for nor` mally urging said actuating'm'ember to saidrst position. i Y i 9. In a Valve. device, the combination of: a housing having a major. bore,4 an intermediate bore, and a minor bore therein in axial align-V ment and having an inletport, a supply port, and an exhaust port; a tubular valve sleeve sta- .tionarily disposed in said major bore and having a main bore and an auxiliary bore axially aligned port communicating between said main bore and saidinlet port and having an rauxiliary valve Yport communicating between said auxiliary bore YandV said exhaust port; a tubular main valve member in said main bore and having a passage therein; Vsaid main valve member' being axially movable inrsaid main bore from a .closed position in Vwhich communication between said inlet port andsaid supply port through said main valve port and said passage is closed to an open position in which said passage and said main valve port provalve member in said auxiliary bore and axially movable relative to said main valve member, said auxiliary valve member normally being out of eniliary valve member intov engagement with saidvr main valve member to close fluid communication between said exhaust port and said supply port through said main valve member and said auxiliary valve port,- and Vthen'to move said auxiliaryV valve member and said main valve member to move said main valve member from said closed position tosaid open position; and spring means closed toan' open position in which saidgpassage .provideswiiuid 'communication between saidinlet 3 port and said supply port,'Y the ends of said'main `valve member being exposed to the fluid pressure' oifsaid supply ,port and ibeing'hydraulically baldisposed in said .intermediate bore for normally maintaining said main valve member and said auxiliary Valve member outof engagement. .r y

i RODNEY B. CAMPBELL. 

